A federal judge has ordered the U.S. Environmental Protection Agency (EPA) to develop plans to mitigate air pollution in upwind states to safeguard downwind states such as Connecticut and New York.

Federal prosecutors on Tuesday ruled in favor of a joint lawsuit filed by Connecticut and New York that claimed the EPA failed to control ozone pollution in nearby states, state officials said.

The lawsuit, filed in January against the EPA and its administrator, Scott Pruitt, states the agency failed to develop new plans that address air requirements for upwind states, which harms the air quality in Connecticut and New York.

Filed in the U.S. District Court for the Southern District of New York, the lawsuit says the EPA's nonaction violated the federal Clean Air Act.

In a June 12 ruling granting plaintiffs' motion for summary judgement, Judge John G. Koeltl enjoined the EPA to "perform its mandatory duty" and promulgate by December an action addressing its obligations under the Clean Air Act's "Good Neighbor" provision.

Gov. Dannel P. Malloy said in a statement the clean air law is crucial to protecting Connecticut residents from air pollution in other states, including West Virginia, Virginia, Ohio and North Carolina.

"As a downwind state, our residents have suffered for too long from other states' lax clean air standards," Malloy said. "The EPA's recent failure to hold upwind states accountable is not acceptable.

Attorney General George Jepsen said his office will continue working with New York officials to hold the EPA "accountable."